Rethinking First-Line Therapy and Beyond: HER2-Positive and Hormone Receptor-Positive/HER2-Negative Metastatic Breast Cancer-Commentary Based on a Live Symposium Presented at the 2025 ESMO Congress in Berlin, Germany.

Recent advances in metastatic breast cancer have fundamentally altered treatment paradigms, offering new hope for patients while challenging clinicians to adapt their approaches to patient care. This article summarizes expert perspectives from a symposium presented at the 2025 European Society for Medical Oncology Congress, examining how emerging data in HER2-positive metastatic breast cancer and hormone receptor-positive metastatic breast cancer are reshaping clinical decision-making, patient selection strategies, and personalized approaches. Key developments include the evolution of antibody-drug conjugates in HER2-positive disease, biomarker-guided therapy selection using ESR1 mutation monitoring, and novel treatment strategies for patients with hormone-refractory disease. These advances necessitate understanding of patient selection criteria, toxicity management, and sequential therapy planning to optimize outcomes in this expanding therapeutic landscape.